Methods:
ASOCT (Visante, Carl-Zeiss Meditec, Dublin) was performed in dark conditions and 2 scans (one vertical and one horizontal) were obtained for all participants. SSOCT 3-dimensional angle scans (CASIA SS-1000, Tomey Corporation, Nagoya, Japan), that obtain 128 radial scans for the entire circumference of the angle, were performed under dark conditions. Iris Trabecular Contact (ITC) index was calculated as a percentage of the angle that was closed on 16/128 SSOCT scans using in-built customized software. Qualitative assessment of angle status was also determined for all 128 SSOCT scans. Angle closure on gonioscopy was defined as non-visibility of posterior trabecular meshwork for at least 2 quadrants. Angle status in anterior segment imaging scans was considered closed if ≥50% of the frames showed angle closure as assessed by a masked clinician. Cohen’s Kappa statistics (k) and area under the receiver operating characteristic (AUC) curve analyses were performed for angle closure based on the 3 types of scan methods in comparison to gonioscopy.